AB0047 THERAPEUTIC POTENTIAL OF COLLAGEN-DERIVED PEPTIDE P90578 IN THE TREATMENT OF RHEUMATOID ARTHRITIS
Authors: Y. L. Cho, C. Wenhart, S. Göbel, A. Reiman, Z. Li, M. Neuhaus, U. Finger, J. Kieselbach, G. Münch
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Antigen-specific peptide immunotherapy is a booming treatment strategy for autoimmune diseases and designs to restore immune tolerance against self-antigens. Published research findings and our previous study using peptides derived from type II collagen with chemical modification such as glycosylation and fructosylation as therapeutics showed promising outcomes in the reduction of arthritis progression<sup>[1,2]</sup>. However, the optimal choice of peptide doses in the rheumatoid arthritis (RA) murine model and its therapeutic effect on human samples still awaits to be investigated. <h3>Objectives</h3> The present study further investigated the optimal dose and therapeutic potential of our novel collagen-derived peptide P90578 in the arthritis murine model and RA patient serum samples. <h3>Methods</h3> Male 8-week-old DBA/1 mice were immunized s.c. at the base of the tail with 0.1 mg bovine collagen II and s.c. at the left flank with 0.2 mg human fibrinogen, each of which was separately emulsified in a 1:1 ratio with complete Freund ́s adjuvant. On day 21 after the immunization, mice were boosted with 0.2 mg human fibrinogen in incomplete Freund ́s Adjuvant s.c. at the left flank. Peptide P90578 or NaCl was intraperitoneally administered three times weekly at 3-day intervals starting on days 7, 24, and 42. Hind paws of the mice were examined for macro-anatomical pathology. Right hind paws of the mice were prepared post mortem and fixed in 4% paraformaldehyde, and embedded in OCT compound. Sagittal sections of 7 μm were cut with an interval of 500 μm and stained with H&amp;E using standard protocols. A histological score was determined based on microscopically pathologic changes of the ankle and tarsal joints. Antibody level against assayed peptides was measured in the serum collected on days 0, 14, 35 and 56 by ELISA assay. Competitive ELISA assays were done by pre-incubation of 10 mg peptide P90578 with sera from RA diseased mice (day 56) and RA patients. Then, the mixture of peptide P90578 and sera was cultured in the plates coated with each of the assayed peptides. <h3>Results</h3> We administered peptide P90578 at a concentration of 1mg/kg, 3mg/kg or 5mg/kg to the arthritic mice. Among the three test groups, the dose of 5mg/kg P90578 revealed the most optimal outcome on arthritis treatment with a reduced severity of tarsal and carpal joint swelling and a lower mean arthritis score compared to the NaCl control (Figure 1A). Hence, we applied the dose of 5mg/kg P90578 in our following experiments. In order to confirm the observation of our findings, we then performed a detailed microscopic examination on the right hind paws. The NaCl-treated mice showed signs of inflammatory cell infiltration, cartilage &amp; bone erosion and typical pannus formation. In contrast, the mice receiving peptide P90578 had structural intact cartilage and minimal infiltration of lymphocytes in the subchondral bone. P90578-treated mice also showed a lower histological score of the joint sections (Figure 1B). Autoantibody levels in all three measurements represented a consistent trend toward decreased antibody titers in the serum of mice treated with peptide P90578 (Figure 1C). Considering the diversity of autoantigens in RA, the cross-reactivity of peptide P90578 binding to each epitope-specific autoantibodies was determined by competitive ELISA. The recognition of autoantibodies against the measured peptide epitopes was reduced by the peptide P90578 about an average of 20% in the RA diseased mice and by approximately 10% in the sera of RA patients, in some cases even exceeding 30% (Figure 1D). <h3>Conclusion</h3> Our study provides evidence showing this novel therapeutic peptide P90578 (5mg/kg) alleviated arthritic burden in the arthritis murine model. Also, autoantibody levels against CCP and peptides derived from collagen and fibrinogen were also reduced after peptide P90578 treatment. Moreover, peptide P90578 can effectively block the binding of autoantibodies in the serum from RA diseased mice and RA patients to the autoantigens. <h3>References</h3> [1]Balik D. <i>et al</i>. <i>J Immunol</i>. 2006; 176 (3):1525–1533. [2]Wenhart, C. <i>et al</i>. <i>Sci Rep</i>. 2021; 11:17345. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.